Hobbing machine



y F. H. ADAMS ET AL ,0 ,8,l73

' HOBBING MACHINE Filed July 21, 1932 'T Sheets-Sheet 1 fimW-Al 404/4; Wynn 64 8mm July 21, 1936.

F. H. ADAMS ET AL HOBBING MACHINE Filed July 21, 1932 7 Sheets-Sheet 2 Arraewsrs July 21, 1936. F. H. ADAMS ET AL 2,048,173

uossme mcnnm Filed July 21, 1932 r Sheets-Sheet s Ilium #6741255 F mew:

July 21, 19.36.

F. H. ADAMS ET AL noasme momma Filed July 21, 1932 l ll l 7 Sheets-Sheet 4 July 21, 1936. F. H. ADAMS ET AL 2,048,173

HOBBING' MACHINE Filed July 21, 1932 v Sheets-Sheet 5 5G /0 hrs/vines.-

Anus-Nays y 1936. F. H. ADAMS ET AL 2,048,173

HOBBING MACHINE Filed July 21, 1932 7 Sheets-Sheet 6 Feww MAIM July 21, 1936.

F. H. ADAMS ET AL HOBBING MACHINE Filed July 21, 1932,

7 Sheets-Sheet 7 r I Q ill lulL WVE/VI'OtS flu/v1 Xi Aawws Mam A $74,155 $444) M Aime/vars Patented July 21, 1936 UNITED sTATEs PATENT OFFICE HOBBING MACHINE a o poration of Ohio Application July 21, 1982, Serial No. 823,830

81Claiml.

The present invention relates to metal working machines and more particularly to bobbing machines of the multiple spindle rotary turret type. wherein a plurality of cutter and work spindles driven at predetermined speeds are rotatably supported on a movable frame, moved in a closed path. and given a relative feeding movement during a portion of the movement in said path.

An object of the present invention is the provision of a novel machine of the type referred to provided with a feed screw for producing the relative feed movement between the work and cutter.

Another object of the invention is the provision of a machine of the type referred to comprising a feed screw and a nut engaging the same for producing the feeding movement, provided with means for producing a rapid traverse movement to return the work and tool supports to their relative starting positions.

Another object of the invention is the provision of a machine of the type referred to comprising a feed screw and a nut engaging the same for producing the feeding movement, provided with a rapid traverse movement to return the work and tool supports to their relative starting positions, which will be automatic in operation.

Another object of the invention is the provision of a novel mechanism for producing "a feed movement between the tool and work in a machine tool and a rapid traverse movement to re= turn the same to their relative starting positions upon completion of the feeding operation.

Another object of the invention is the provision of a mechanism for producing relative feed movement between work and tool supports which comprises a feed screw and a novel split nut adapted to engage said feed screw during the 40 feeding operation and be moved clear of the same to permit a return movement of said supports to their starting positions.

Other objects of the invention are the provision of a novel fluid system for supplying coolant to a plurality of tools during the working operation thereof. and a novel cascade oiling system for supplying lubricant to a plurality of bearing surfaces.

The invention resides in certain novel features, details of construction, and combinations and arrangements of parts, and further objects and advantages thereof will be apparent to those skilled in the art from the following description of the preferred embodiment thereof described with reference to the accompanying drawings. in which Fig. 1 is a perspective view of a bobbing machine embo ying the present invention.

Fig. 21s a section of the machine shownin 5 Fig. 1 approximately on the center line with portions shown in elevation etc.

Fig. 3 is an enlarged view of a portion of Fig.

2, with a portion broken away.

Fig.4isaviewontheline4--4ofFig.8,look- 10' ing in the direction of the arrows.

Flg.6lsaviewontheline85ofFig.8looking in the direction of the arrows.

Fig. 6 is a section on the line 8-4 of Fig. 2 looking in the directionof the arrows.

Fig. 7 is a section on the line 1-! of Fig. 8 looking in the direction of the arrows.

Fig. 8 is a section on the lines 8l of Figs. 4 and 7 looking in the direction ofthe arrows.

Fig. 9 is a section on the line 9-9 looking in the direction of the arrows.

Fig. 10 is a section on the line i0-l0 of Fig.

8 looking in the direction of the arrows.

Fig. 11 is a section approximately on the line M of Fig. 2 looking in the direction opposed to 25 the arrows, and on the line ii-ii of Fig. 1.? looking in the direction of the arrows, showing a plan elevation of a modified construction of feeding mechanism.

Fig. 12 is a front elevation. with parts broken 30 away, of the device shown in Fig. 11, looking from the bottom of Fig. 11.

Fig. 13 is an elevation of the device shown in Figs. 11 and 12, looking from the left, similar to v Fig. 3 but showing the modified construction. 35

Similar reference characters designate corresponding parts throughout the several views of the drawings.

The preferred embodiment of the invention is illustrated as embodied in a machine somewhat similar to the machines illustrated in United States Patents Nos. 1,732,700; 1,878,656; 1,973,133, and only those parts of the machine are illustrated which are necessary to convey a complete understanding of the invention to those skilled in the art.

The invention may be summarized as comprising a frame A, a turret B rotatably supported by the frame A, a plurality of hobbing units supported by the turret and comprising tool or hob heads C, work heads D, paired with the hob heads, driving mechanism E for rotating the hob and work spindles at predetermined speeds, and feed mechanism designated in general by the reference character F for producing relative feed movement between the work and tool heads during the rotation of the turret B about the frame A.

In the embodiment of the invention illustrated the turret B is continuously rotated in the direction of the arrow R, and the work spindles loaded and unloaded as the hobbing units, of which there are eight, successively pass a deflnite position referred to as the loading station. As the hobbing units are carried in a closed path about the axis of the turret and returned to the loading station the work heads D are moved vertically on the turret B by the feed mechanism F to feed the work past the cutter. The tool heads 0 are preferably adJustably supported by the turret B for movement in a plane normal to the vertical movement of the work heads D, but it is to be understood that a relative feed between the tool and work spindles normal to the turret axis may be provided in addition to the relative movement longitudinally of the work spindle axes.

The frame A comprises a base I0 and a central column II about which the turret.B is rotatably supported by suitable bearings I2, I3 and I4. The

turretB is rotated about the frame A by a motor I5, through a worm and a worm wheel I! and i 8 respectively. The worm wheel I8 is of large diameter and is bolted on a. flange member I9 secured by the bolts 26 to the lower part of a member'ZI which forms the main frame of the turret B.

The tool heads C comprise tool or hob spindles 36 rotatably supported by spindle members 3I which in turn are supported by head members 32 and adjustable about axes normal to the axes of the hob spindles 80. The head members 32 are slidably' supported on horizontal ways on the turret member 2i and adjustable therealong radially of the axis about which the turret rotates by screws 33 engaging the head members and threaded into tapped holes in the turret member 2|. The work heads D comprise work spindles 35 rotatably supported in work head members 36 by anti-friction bearings 31 and 38 and tail slides 39 slidably supported on ways 46 on vertical projections 4I of the work head members 36 and held in any adjusted position by the clamp levers 42. The head members 36 are slidably supported on vertical ways 43 and 44 on the turret member 2| and a cap member 45 secured to the top of said turret member by the bolts 46 and moved therealong by mechanism hereinafter referred to. A collapsible wayguard 41, not shown in Figs. 2 et seq. is used to protect the ways 43 from chips etc.

The hob and work spindles 36 and 35 respectively are rotated at predetermined relative speeds by a motor 34 supported on an adjustable platform 48 on the top of the column II and operatlvely connected to a shaft 49 through a flexible drive 50. A pinion 5i keyed to the shaft 49 meshes with a bevel gear 52 bolted to the upper end of a sleeve. 53 rotatably supported by antifriction bearings 54 and 55 on the central column II. Spacer sleeves 56 and 51 position the bearings 54 and 55 on said column. A bevel gear 58 bolted to the lower end of the sleeve 53 meshes with a plurality of bevel pinions 59, one for each hobbing unit, keyed to short shafts 6D rotatably supported in the turret member 2i by anti-friction bearings 6i and 62.

The drives for the various hobbing units from the gear 58 are duplicates and merely one of them will be referred to in detail. 60 is operatively connected to and drives a spline shaft 63, rotatably supported in a member 64 bolted to the turret member 2| by a bevel gear 65 splined to said shaft and an anti-friction bearing 66, and the head member 32 by an antifriction bearing 61, through a friction plate clutch 68 the driven member of which is splined to said shaft 63. The clutch 68 is adapted to be either manually or automatically operated in predetermined timed relation to the other operation of the machine through mechanism designated in general by the reference character 69, adapted to be automatically operated by cam mechanism I0 controlled by the vertical movement of .the work head D. The hob spindle 30 is driven from the shaft 63 through miter gears H and i2 keyed to the shaft 63, a short shaft 13 rotatably supported in the spindle member 3|, and change gears, not shown, one of which is keyed to the shaft 13 and the other to the spindle shaft 30. The spline shaft 63 permits adjustment or movement of the hob head C radially of the turret axis without interruption of the hob spindle drive, and the miter gears II and I2 permit angular adjustment of the spindle member 3i and the hob spindle 30 about the axis of the shaft 63. v

The work spindle is driven. from the shaft 63 through the bevel gear 65, previously referred to, which meshes with a bevel gear 15 keyed to the upper end of a vertical shaft 16 rotatably supported by an anti-friction bearing 11 in the member 64. A bevel gear 80, splined to the lower end of the shaft 16, rotatably supported in a projection 8i on the rear of the work head member 36, meshes with a bevel gear 82 keyed to a short shaft 83 the other end of which carries a spur gear 84 also keyed thereto. A spur gear 85 keyed to a shaft 86 rotatably supported on the work head member 36 meshes with the gear 84. The shaft 86 is operatively connected to the work spindle 35 through change gears 81, a shaft 88 rotatably supported in the member 36 and connected to one end of the train of change gears 81, and a worm 89 keyed to the shaft 88 and in mesh with a worm wheel 90 keyed to the work spindle 35.

Oil is supplied to the various bearings by a cascade system which includes a pipe 91 through which oil is pumped from a reservoir in the base of a machine by a pump 98 of any desired construction, to a small reservoir 99 at the top of the column I I. From the reservoir 99 the oil flows down the outer surface of the column II, lubricates the bearings 54, 55, I2, I3 etc., and also over the bevel gear 52 onto a ledge I 00 formed integral with the cap member 45. From the ledge I 80 the oil is conducted by a pipe or pipes IIH to a trough on the top of the turret member 2| from which it passes to the bearings GI, 62 etc. Oil is also conducted from the reservoir 99 to the front bearings of the tool head by pipes I03, see Fig. l.

The lubricating and cooling fluid for the cutting tools is supplied from a reservoir H8 in the base III of the machine, from where it is pumped by a pump II2 to a small annular reservoir I I4 at the top of the turret B through pipes II 5 and H6, connection I", and pipe H8. The pipe 6 projects up through the center of the column Ii and the connection I I 1 is bent to accommodate the shaft 49. The reservoir H4 is provided with an overflow pipe I20. A plurality of nozzles I22, one at each hobbing unit, are connected to the reservoir II4 by pipes I23. The flow of fluid The shaft through the nozzles I22 is controlled by valves I24 either manually or automatically operated. The valves I24 are preferably operatively connected by a rod I25 to the clutch operating mechanism 69 and operated thereby in such a manner that the flow of fluid is interrupted when the spindles 30 and are stationary in the loading station, and uninterrupted during the rotation of said spindles.

The machine thus far described is similar to those illustrated and described in the above referred to patents, differing therefrom in certain features and details of design and construction illustrated in the drawings and referred to above, to produce a new and improved machine which will be more accurate and'rugged, and simpler in construction.

As previously stated the hobbing' units are carried in a closed circular path about the axis of the turret B as the 'same rotates, and the work loaded and unloaded at one or more positions referred to as loading stations. In the embodiment of the invention illustrated, only one loading station is employed at which position the finished work is removed and a new work piece inserted without interrupting the rotation of the turret. During the rotation of the turret B the work heads D which are not in'the loading station are moved along the vertical ways 43 and 44 to feed the work supported thereby past the cutters or hobs carried on the spindles 30. As the hobbing units successively pass the-loading station, the finished work piece is removed, a rapid traverse movement imparted to the work heads D to lower the same to the starting position, and a new work piece inserted. The mechanism, to be described presently, for producing the feed and rapid traverse movement of the work heads D comprises a cam member I60 positioned at the loading station,

supported by the base I0, and provided with three cam surfaces l6I, I62 and I63, and the mechanism F carried by the turret-B which is duplicated at each of the work heads D. Since the mechanism F is duplicated at each of the heads only that at one of said heads will be described in detail.

A bracket I65'secured to the lower ends of the ways 43 by the bolts I66 and I61 supports a split nut N adapted to engage a lead screw I 10 rotatably secured in a suitable aperture I1I in the work head member 36. The lead screw I10 is rotated in predetermined timed relation to the other operations of the machine, from the work spindle 35 through change gears indicated in general by the reference character I13. An antifriction thrust bearing I15 is positioned between the lead screw I10 and the work head member 36 to take the weight of the work heads D.

The two halves I18 and I19 of the split nut N are carried in semi-circular apertures I80 and I 8I, in levers I82 and I83 pivoted to the bracket I65 by the bolts I84 and I85, and retained therein by plates I86 and I81 secured to the arms I82 and I83 respectively by countersunk screws I88. The split nut N is adapted to float in the levers l 82 and I83 and is provided with upper and lower flanges I92 and I93 which project over said levers and limit the movement of the nut therein. The nut N is held in a mid-position with reference to the levers I82 and I83 by upper and lower coil springs I94 and I95 positioned in suitable apertures in the levers. The upper springs I94 are of greater tension than the lower springs I95 and project merely a short distance above the levers I82 and I83. The lower springs I95 respectively by the screw I99.

are set in cup members I96 which engage the lower flange I93 of the nut N (see Fig. 8). The two halves I18 and I19 of the split nut N are retained in proper horizontal alignment by plates I91 and I98 positioned in a cutaway portion of 5 the nut and secured to the halves I18 and. l19

The levers I 82 and I83are moved about their pivots. I84 and I85 to open and close the nut N about the lead screw I10 by a cam'plate 200 ro- 10 tatably supported on a pivot 20I secured to, an upwardly extending projection 202 on the bracket I65, and provided with spiral cam grooves 204 and 205' into which pins206 and-.201 secured to the levers I82 and I83 respectively project. A 15 downwardly projecting arm 209 on the cam plate 200 projects through a slot 2I0 in the bracket I65 and carries a roller 2I2 on the lower end thereof adapted to engage the horizontal cam surface I62 on the projection 2 ,of the cam 20.

member I 60, see Fig. 3, where the cam member I60 is shown in dot and dash lines, as the same is carried past the cam member I60 by the. r0,- tation of the turret B. The cam .plate 200 is continuously urged in a clockwise,dir'ection-, as.25 viewed in Figs. 5 and 9, that is, in a direction to; move the levers I82 and I83 to close. the split nut N, by a coil spring 2 one end of which is connected to the cam plate 200 by a screw 2. I4 a and the other end connected to a screw. -2I6 30 secured to the projection 202. In operation, the.

roller 2 I2 engages the cam surface I62 on the sta-. tionary cam member I60 as the workhead-is carried through the loading station by the-rotation of the turret, and the cam plate 200 rotatedto 135:.

disengage the split nut N with the lead screw- I 10, 4 thus permitting the work head to be lowered to its starting position, etc., by the followirig mechanism.

As the work head D approaches the loading station, the weight of the same is shifted from the lead screw 110 before the split nut N is opened onto a roller 220 supported in the lower end of a bracket 22I bolted to the lower surface of the work head member 36, by the engagement of said roller with a. high portion a ofthecam surface I6I on the cam member I60. After the split nut N is opened, continued rotation of. the turret B causes the roller 220 to roll down the inclined portion 12 of the cam surface -I6I and lower the work head D. During the movement of the roller 220 along the horizontal portion c of the cam surface I 6|, time is provided for positioning a new work piece in the work support. As the roller 220 rolls up the inclined portion d of said cam surface the work is brought up to the cutter with a quick movement, after whichv the split nut closes and the weight of the work head is again shifted to the lead screw I10 as f the roller 220 rolls along the upper horizontal 69 portion e of said cam surface.

The split nut N rests upon a circular plate 225 positioned in an aperture 226 in the bracket I65, which plate takes the weight of the work head in place of the arms I82 and .183. The 55.

plate 225 is raised immediately after thesplit nut closes, to lift said nut and completely engage the threads thereof with the threads of the lead. screw I 10 without delay and before the weight of the work head is shifted back to said lead 7:

screw, by rotation of a cylindrical member 221 threaded into an aperture 228 in the bracket I55 and provided with a central opening 229 through which said lead screw may project. The cylindrical member 221 is provided with coarse square threads 230 and has a lever 232 keyed to the lower end thereof. A coil spring 235, one

end of which is secured to the lever 232 by ascrew 236 and the other end to a bolt 231 threaded into the bracket I65, continuously urges said lever in a counterclockwise direction as viewed in 4, that is, in a direction to raise the plate 225 and the split nut N. Movement of the lever 232 under the action of the spring 235 is limited by a fixed stop 238 secured to the bracket I65. The cylindrical member 221 is rotated in the opposite direction at the loading station after the weight of the work head D has been shifted to the roller 220 by the engagement of the projecting end 239 of the lever 232 with the vertical cam surface I63 on a downwardly projecting portion 240 on the cam member I60. The plate 225 remains at the bottom of the aperture 226 until after the split nut N closes, after which the' carried in the closedpath about the axis of the turret B, the work pieces supported by the work heads are fed past the cutters by the lead screws I which aredriven from the work spindles 35. As the hobbing units successively reach the loading station the rotation of the spindles and the lead screw of that particular unit is stopped by the automatic release of the clutch '68 which interrupts the drive to that particular hobbing unit. At about the same time the weight. of the i work head D is shifted to the roller 220 follow-' ing which the roller 2I2, and the end 239 of the lever 232, engage the cam surfaces I62 and I63 respectively opening the split nut N and lowering the plate 225. The finished work piece is then removed from the work head and the roller 22!! rides down the inclined portion b of the cam surface I6I, producing a rapid return movement of the work head D to its initial or,

lower position. As the roller 220 travels along the horizontal portion C of the cam surface I 6| a work piece to be machined is positioned in the work supports of the work head, following which the work head is elevated by the inclined portion d of said cam surface to quickly bring the work to the cutting position, at about the same time the clutch 68 is again operated to connect the drive to the spindles etc. After the work head has been elevated to the cutting position, the roller 2I2 clears the cam surface I62 permitting the split nut N to close under the action of the spring 2I3. The end 239 of the lever 232 then clears the cam surface I63 allowing the cylindrical member 221 to be rotated by the action of the spring 235 to raise the plate 225 and the nut N. The cycle of operation is then repeated, may be continued indefinitely, and is the same for all the hobbing units. The reference character 24I indicates a cover for the mechanism F and the reference character 242 a splash guard about the base of the machine. The section 243 of splash guard at the loading station is not as high as the other sections.

A modified construction of the feeding mechanism shown in Fi s. 1 to 10 inclusive is illustrated in Figs. 11, 12 and 13. The bracket 245 together with the mechanism carried thereby indicated in general by the reference character F is adapted to be substituted, as illustrated, for the bracket I65 together with the mechanism carried thereby and indicated in general by the reference character F.

In the modification illustrated in these figures, the two halves 246 and 241 of the split nut N are slidably supported in suitable ways 248 formed in a member 250. The member 250 is slidably supported for vertical movement in the bracket 245 by members 25I and 252 secured to the member 245 by the bolts 253. The two halves 246 and 241 of the split nut are moved to engage and-disengage the lead screw I10 by a cam plate 255 slidably supported in the bracket 245 for vertical movement, and provided with cam grooves 256 into which pins 258 and 259 carried by the halves 246 and 241 respectively of the nut N project.

The cam plate 255 is continuously urged in an upward direction by a spring 260 supported by the bracket 245 and projecting into a suitable aperture 26I part of which is in the member 250 andpart in the cam plate 255, see Fig. 13. The upper end of the spring'260 engages a cupshaped member 262 which has a sliding fit in the aperture 26I. The part of the aperture 26I in thecam plate 255 is shorter than the part in the member 250, which permits free movement of the cam plate 255 relative to said member. The cam plate 255 is moved in a downward direction to open the split nut by the engagement of a roller 265 carried thereby underneath a cam member 266 positioned at the loading station. The cam member 266 is preferably attached to the cam member I66, replacing the projection 2I3-on said member upon which the cam surfaces I62 and I 63 are formed.

When the upward movement of the cam plate 255 is stopped by the seating of the pins 258 and 259 in the bottom of the grooves 256, or before the pins reach the bottom of the grooves if the nut N does not properly close on the threads of the lead screw I16, the entire assembly 250 is raised by the spring 260, permitting the nut to quickly close about the lead screw. The member 250 is held in this elevated position by a stepped wedge 268 which engages the lower surface thereof and is continuously urged toward the left, as viewed in Figs. 11 and 12, by a compression spring 269. Thewedge 268 is withdrawn from underneath the member 250 at the loading station by the engagement of a projection 21I on a lever 212 underneath the cam member 266. The lever 212 is keyed to one end of a short shaft 213 rotatably supported in a boss 214 in the upper end of a projection 215 on the member 252. A lever 211 keyed to the opposite end of the shaft 213 is gperatively connected to the wedge 268 by a link The operation of the device is similar to that of the preferred construction. As the work heads D are successively brought to the loading station by the rotation of the turret B, the weight thereof is shifted from the lead screw I16 to the roller 220 in a manner previously referred to. The roller 265 rides under the cam member 266, opening the split nut, and the wedge 268 is withdrawn by the engagement of the projection 2" under the same cam member. Thereafter the finished work piece is removed, the work head returned to its lower position, a new work piece positioned in the work supports, and the work nut with said lead screw whereby said slide ishead raised to bring the work into cutting position as described with reference to the preferred construction. After the work has been moved up to the cutter the roller 265 clears the cam member 266, permitting the split nut N to be closed by the action of the spring 260, following which the projection 2' on the lever 212 clears said cam member, permitting the wedge 268 to move underneath the member 250 by the action of the spring 269.

From the foregoing description it will be apparent that a new and improved machine and feed mechanism therefor has been provided. The embodiments of the invention shown are merely illustrative of the invention, and we do not wish to be limited to the particular construction illustrated and described which may be varied within the scope of this invention. The cam surfaces d and e on the cam member I60 illustrated in the preferred embodiment may be omitted and the surface c extended, permitting the work heads D to be entirely raised by the feeding movement without the rapid traverse movement to bring the work to the tool. The spindles and the lead screws may be continuously rotated and the loading and unloading of the work spindles performed without stopping said spindles. A clutch may be interposed in the lead screw drive whereby the feed may be stopped without stopping the work spindles, or the drive for the lead screw may be taken from some part of the machine other than that illustrated. The work and tools may be interchanged, or the lead screws positioned above the tool spindles instead of below, as illustrated. The units may be driven by individual motors and the machine may be set up to machine various pieces of work besides splined shafts, spur gears, spiral gears, bevel gears, spiral bevel gears, etc., and the cutter may be either a cylindrical, conical, or face hob, or any mill cutter, etc. The adjustments of the spindles permit the cutting of such articles as spiral bevel gears with face hobs.

As previously stated, we do not wish to be limited to the particular construction illustrated and described which, as shown, may be varied, and we particularly point out and claim as our invention the following:

1. A machine of the character described comprising a. base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a member movably supported by said turret, a lead screw for moving said member relative to said turret, a split nut adapted to en gage and disengage said lead screw, means controlled by the rotation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to produce relative movement between said nut and said lead screw while said nut is disengaged from said lead screw to return said member to its original position. I

' 2. A gear cutting machine comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a slide supported by said turret, a spindle rotatably supported by said slide, a lead screw for moving said slide relative to said turret, a split nut adapted to engage and disengage said lead screw, common means for rotating said spindle and producing relative rotation between said nut and said lead screw, means controlled by the rotation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to produce relative movement between said nut and said lead screw during the disengagement of said returned to its starting position.

3. A machine of the character described comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a plurality of spindles rotatably supported by said turret, a lead screw for moving one of saidspindles relative to the other, a split nut adapted to engage and disengage said lead screw, means controlled by the rotation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to produce relative movement between said nut and said lead screw while said nut is disengaged from said lead screw to return said slide to its starting position.

4. A gear cutting machine comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a plurality of spindles rotatablysupported by'said turret, a lead screw for moving one of said spindles relative to the other, a split nut adapted to engage and disengage said lead screw, common means for rotating said spindles and producing relative rotational movement between said nut andlsaid lead screw, means controlled by the retation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to produce relative movement between said nut and said lead screw during the disen-' gagement of said nut with said lead screw whereby said slide is returned to its starting position.

5. A gear cutting machine comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said-base,".a plurality of spindles rotatably supported by said turret, a lead screw for moving one of said spindles relative to the other, a split nut carried by said turret adapted to engage and disengage said lead screw, means controlled by the rotation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to move said lead screw relative to said nut while said nut is disengaged from said lead screw to return said spindles to their relative starting positions.

6. A machine tool comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a plurality of spindles rotatably supported by said base, a lead screw for moving one of said spindles relative to the other, a split nut carried by said turret adapted to engage and disengage said lead screw, common means for rotating said spindles and said lead screw, means controlled by the rotation of said turret for engaging and disengaging said nut with said lead screw, and means adapted to move said lead screw relative to said nut during the disengagement of said nut with lead screw whereby said spindles are returned to their relative starting positions.

7. A machine tool comprising a base, a turret rotatably supported by said base, means for rotating said turret relative to said base, a plurality of spindles rotatably supported by said turret, a lead screw for moving one of said spindles relative to the other, a pair of arms pivotally supported by said turret, a split nut carried by said arms adapted to engage and disengage said lead screw, means controlled by the rotation of said turret for moving said arms to engage and disengage said nut with said lead screw, and means adapted to move said lead screw relative to said nut while said nut is disengaged from said leadscrew to returnsaid spindles to their relative starting positions. I v

8. A multiple hobbing mac e -comprlsingpa base, a turretrotatablysupported by said base, means for rotating said turret; relative to said base, a plurality of spindlesrotatably supported by said turret, a lead screw for moving ,one of said spindles relativeto another, a split nut comprising two halves slidably supported by said turret adapted to engage and disengage-said. lead screw, means controlled by therotation of said turret for reciprocating the halves oflsaid nutto engage and disengage said out with said lead screw, and means adapted to-move said lead screw'relative to said nut while said-nut is disengaged from said lead screw to return said spindles to their relative starting positions; v

9. In a machine of the character described, the combination of a frame,-a member movably supported by said frame, means-for moving'said member including a-lead. screw and a split nut,

means for engaging and disengaging said split nut with said. lead screw, asecond member threaded; into an aperture in said frame and engaging said split nut, and means for rotating said member at predeterminedintervals whereby said split nut :is moved longitudinally-of said lead.

screw. Y

10. In amachine. of the character described, the combination of a base, aturret rotatably supported by said base, means for rotating said turret, a member movably supported by said turret, means including --a lead screw..- and' a 1 split. put

for moving said'member-relativeto'said turret, saidsplit nut comprising a:.,;plurality oLparts movable towards .andfrom said-lead screw, means for moving said split nut to" engage and disen- 4 gage said lead screw at predetermined intervals,

and means for producingv relative-movement be-'- whentween said lead screw and. said split out the same is disengaged therefrom. Y

11. In a .machineof the character described,

the combination of a base, a turret rotatably supported by said base, means .for rotating .said turret, a member movably supported by said turret, means including a lead screw and a split nut for 12. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a member movably supported by said turret,

a lead screw engaging saidmember for moving the same, a split nut supported by said frame,

means for automatically engaging anddisengaging said split nut with said lead. screw. at predetermined intervals, and means formoving said split nut longitudinally of said lead screw.

13. In a machine of the character described, the combination of a base, a-turret rotatably supported by said base, means for rotating said turret, a member movably supported bysaid turret, a lead screw engaging said member for moving the same, a split nut supported by said frame, means for automatically engaging, and disengaging said split nut with said lead screw at predetermined intervals, means for producing relative rotation between said' lead screw and 'said" split nut, and means comprising a member having threaded engagement with said frame for moving said split nut longitudinally of said lead screw.

14. In a machine of the character described, 5 the combination of a base, a turret rotatably supported bysaid base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said units comprising a member slidably supported by said turret and a cooperating lead screw and nut for moving said member relative to said turret, means for producing relative rotation between respective lead screws and nuts whereby said members are moved in sequence in one direction, and means controlled by the rotation of said turret for automatically moving said members successively in an opposite direction.

l5. In a machine of the character described. the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each ofsaid units comprisinga member movably supported by said turret, a pl rality ofcooperating lead screws and split nutsfor moving said members relative to said turret, means for opening and closing said split nuts about their respective lead screws in sequence at predetermined intervals, means for producing relativerotation between said lead screws and said split nuts whereby said members aremoved in sequence in one direction, and means for producing relative movement between said lead screws and said split nuts when the same are disengaged from said lead screws to return saidmembers to their starting position.

16. Inc. machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported 40 by said turret, each of said units comprising a membermovably supported by said turret, lead screws and cooperating split nuts for moving said members relative to said turret, means for producing relative rotation between said lead screws and their respective split nuts, means controlled by the rotation of said turret for automatically opening and closing said split nuts at predetermined intervals, and means controlled by the rotation of said turret for producing relative movement between said lead screws and said split nuts during the interim that said split nuts are open for returning said movable members to their starting position.

17. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said units comprising a member movably supported by said turret and a cooperating lead screw and split nut for moving said members relative to said turret, means controlled by the rotation of said turret for automatically opening and closing said split nuts at predetermined intervals, means controlled by the rotation of said turret for producing relative movement between said lead screws and their respective split nuts during the interim that said split nuts are open for returning said movable members to their starting position, and means for moving said split nuts longitudinally of said lead screws."

18. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating, said turret, a plurality of metal working units supported by said turret, each of said units comprising a member movably supported by said turret and a cooperating lead screw and split nut for moving said members relative to said turret, means controlled by the rotation of said turret for antomatically opening and closing said split nuts successively, means controlled by the rotation of said turret for returning said members to their starting position during the interim that said split nuts are open, and means comprising a member having threaded engagement with said turret for moving said nuts longitudinally of said lead screws immediately upon the closing thereof.

19. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said metal working units comprising a member movably supported by said turret and a cooperating lead screw and split nut for moving said member relative to said turret. means for producing relative rotation between said lead screws and their respective split nuts. means controlled by the rotation of said turret for opening said split nuts successively at predetermined intervals, means controlled -by the rotation of said turret for producing relative movement longitudinally of said lead screws between said lead screws and the respective split nuts with which they engage upon the opening or said split nuts, means controlled by the rotation oi said turret for closing saidsplit nuts successively, and means controlled by the rotation of said turret for producing relative movement of said split nuts longitudinally of said lead screws immediately upon the closing of said split nuts.

20. In a machine of the character described the combination of a base, a turret rotatablysupported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said units comprising a member slidably supported by said turret and 'a lead screw operatively connected thereto, a plurality of split nuts supported by said turret'and operatively engaging said lead screws, means controlled by the rotation-of said turret for opening and closing said split nuts successively, means controlled by rotation of said turret for moving said lead screws relative to said split nuts during the interim that said split nuts are open, and means for moving said split nuts longitudinally of said lead screws immediately upon closing thereof about said lead screws.

21. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said units comprising 'a member slidably supported by said turret and a lead screw operatively connected thereto, a plurality of split nuts supported by said turret, each of said split nuts comprising a plurality of parts pivotally supported on said turret adjacent said lead screws, means controlled by the rotation of said turret for moving said parts relative to said lead screws whereby said split-nuts are successively engaged and disengaged therewith, means for producing relative rotation between said lead screws and said split nuts, and cam means for moving said lead screws relative to said split nuts during the interim that said split nuts are disengaged therewith.

22. In a machine of the character described the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of .said units comprising a head movable radially --of the axis of saidturret and a .second head movable parallel with 'the axis-of said turret, means .-for moving one of said heads of "each unit :relative to said turret comprising lead screws and cooperating split nuts, :means for producing relative rotation between said lead screws and their respective split nuts, means-controlled by the rotation of the turret for engaging and disengaging the split nuts with their respective lea-d screw successively, and means for producing. relative movement between respective lead screws and split nuts longitudinally of said lead iscrews during the interim that said splitmuts are disengaged from the lead screws.

23. In a --machine of the character described,

the combination-otabase, a turret-rotatablysupported by-sa'id base, means forrotating'said turret, a plurality oi-gearcutting units supported by said turret, each :of :said .units comprising a work head and a tool head slidably supported by said turret and .movable' fz'in planes normal to each other-one-ci'which isnormal to the axis at said turret, spindles rotatably supported by one of said 'heads'ioi'each ,o'I-saidunits-means for rotating said spindles, leadscrews ion-moving one of said heads of veacl'lie'i said :units relative-to said turret, means for rotating said lead screws in predetermined'timed relation to the rotation 01 said spindleoif'theunit' with which they are a sociated, aplurality ofrsplit nuts cooperating with .said flead screws, means .for actuating said split nuts to :engage :and disengage their respective lead screws, and-stationary cam :means supported by said base :for actuating said last :mentioned means at predeterminediintervals.

:24. In a :machine -c'! the character :described. the-combinationoiaibasea turreturotatably supported by said base, means for rotating said tur ret, a plurality ofsgear-cutting units supported by said turret, .eachoi said'units-comprising a work head and -a tool headslida'bly supported by said turret and -moyable .in planes 'normal to each other On9'Of"Wh10hiiS "normal to 'the axis of said turret, .spindles'rotatably supported by one of said heads of each of said units, means for rotating said spindles, lead screws for moving one o! saidheads of each of said units relative to said turret, means .tor rotating said lead screws from said spindle oi the -unit.with which they are associated,-a pluralityotsplit nuts cooperating with said lead screws, means for actuating said split nuts to engage. and disengage the respective lead screws with which they cooperate, and stationary cam means supported by .said base for actuating said last mentioned means at predetermined intervals.

25. In a machine of the character described, the combination 01 a base, a turret rotatably supported by said base,.means for rotating said turret, a plurality of metal working units supported by said turret. eaehoi said units comprising a member movably supported by said turret and means for moving said member relative to said turret comprising a cooperating lead screw and split nut, said split qnuts comprising a plurality of partsmovable radially of the axis of said lead screw, means forxactuating said split nuts for engaging and disengaging the respective lead screws with which they cooperate comprising cam members movably supported by said turret, a stationary cam supported by said base and means on said cam members for engaging said stationary cam at predetermined intervals during the rotation of said turret whereby said split nuts are actuated successively at predetermined intervals, and means for moving said lead screws relative to said split nuts during-the interim that said split nuts are disengaged with their respective lead screws to return said members to their starting position.

26. A metal working machine of the character described comprising means for supporting a work blank, means for supporting a tool, means comprising a lead screw and a cooperating split nutfor producing a relative feed movement between the first two mentioned means, means for producing a relative rotation between said lead screw and split nut for effecting said feed movement, said split nut comprising a plurality of parts movable relative to said lead screw, means for moving the parts of said split nut to engage and disengage said lead screw, and means supplemental to the normal relative feed producing rotation between said lead screw and said split nut for producing relative movement between the lead screw and cooperating split nut taking up lost motion between the threads thereof.

27. In a machine of the character described, the combination of a base, a turret rotatably supported by said base, means for rotating said turret, a plurality of metal working units supported by said turret, each of said units com prising a member movablysupported by said turret, lead screws and cooperating split nuts for moving said members relative to said turret, means for producing relative rotation between said lead screws and their respective split nuts to produce a feed movement, means controlled by the rotation of the turret for automatically opening and closing the split nuts about their respective lead screws at predetermined intervals, means controlled by the rotation of said turret for producing relative movement between said lead screws and said split nuts during the interim that said split nuts are opened for restoring said movable members to their relative starting positions, and means supplemental to the normal relative feed producing rotation between the split nuts and their respective lead screws for taking up lost motion between the threads thereof.

28. A metal working machine of the character referred to comprising a base, a turret rotatably supported by said base, a plurality of metal working units supported by said turret, means for rotating said turret whereby said units are moved in sequence through a loading station, each of said metal working units comprising a member slidably supported by said turret and a cooperating lead screw and nut for moving said member relative to said turret, and means for producing relative rotation between said lead screws and nuts.

29. A metal working machine of the charac ter referred to comprising a base, a turret rotatably supported by said base, and a plurality of metal working units supported by said turret, means for rotating said turret whereby said units are moved in sequence through a loading station, each of said metal working units comprising a tool support, a work support, a cooperating lead screw and nut for producing relative feed movement between said supports, and means for producing rapid traverse movement between said supports.

30. A metal working machine of the character referred to comprising a base, a turret rotatably supported by said base, and a plurality of gear cutting units supported by said turret, means for rotating said turret whereby said gear cutting units are moved in sequence through a loading station, each of said gear cutting units comprising a rotatable tool support, a rotatable work support, a cooperating lead screw and nut for producing relative linear feed movement between said supports, common means for rotating one of said supports and producing relative rotation between said lead screw and nut, and means for producing rapid" traverse movement between said supports.

31. A metal working machine of the character referred to comprising a base, a turret rotatably supported by said base, a plurality of gear cutting units supported by said turret, means for rotating said turret whereby said gear cutting units are moved in sequence through a loading station, each of said gear cutting units comprising a rotatable tool spindle and a rotatable work spindle, means for producing a relative feed movement between the tool and work spindles of each unit, and means for producing a rapid traerse-movement between the tool and work spindles of each unit, said second mentioned means comprising a cooperating lead screw and nut for each unit and means for producing relative rotation therebetween.

FRANK H. ADAMS. WILLIAM H. STAPLES. 

